Disable wxUSE_FSWATCHER under Unix if neither inotify nor kqueue is available.

Don't define wxUSE_FSWATCHER as 1 in configure if we can't implement it.

Also add a check to wx/unix/chkconf.h to verify that we didn't end up with an
inconsistent configuration somehow.

Closes #11670.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63306 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/unix/chkconf.h

@@ -21,6 +21,17 @@
 #   endif
 #endif /* wxUSE_CONSOLE_EVENTLOOP */
 
+#if wxUSE_FSWATCHER
+#   if !defined(wxHAS_INOTIFY) && !defined(wxHAS_KQUEUE)
+#       ifdef wxABORT_ON_CONFIG_ERROR
+#           error "wxFileSystemWatcher requires either inotify() or kqueue()"
+#       else
+#           undef wxUSE_FSWATCHER
+#           define wxUSE_FSWATCHER 0
+#       endif
+#   endif
+#endif /* wxUSE_FSWATCHER */
+
 #if wxUSE_GSTREAMER
 #   if !wxUSE_THREADS
 #       ifdef wxABORT_ON_CONFIG_ERROR